Automatically stop recording after 30 seconds of silence

Special Interest Groups Recording Techniques
1

I have several cassette tapes I am converting to mp3 and it would be helpful for Audacity to automatically stop recording after 30 seconds of silence, like when the cassette ends.

2

Audacity can “pause” when the sound level drops.
See “Sound Activated Recording” http://manual.audacityteam.org/man/Transport_Menu#sar